Traversing mechanism

ABSTRACT

An apparatus for winding continuous strands of material about rotating cores to form strand packages is provided with primary traversing mechanisms which impart a primary traversing motion to the strands as they are being wound on the packages whereby the strands progress and regress to define a series of bights. A secondary traversing mechanism is provided to impart a secondary traversing motion of the strands relative to the packages to advance the series of bights back and forth across the peripheral face of the packages. The primary traversing mechanisms each comprise a first series and a second series of cam members having outwardly facing convex surfaces for engaging the strands. The convex surfaces of the cam members of the first and second series face in opposing directions with the convex surfaces for successive cam members of each series being progressively displaced relative to preceding cam members in a direction parallel to the axis of rotation of the traversing mechanism. With this construction the first series of cam members move the strands in one direction and the second series of cam members move the strands in an opposite direction.

ilnited States Patent Mohr et al. .1 Jan. 21, 1975 TRAVERSING MECHANISMPrimary ExaminerStanley N. Gilreath [75] Inventors: John Gilbert Mohr,Maumee; James Attorney 4 Firm Robert Krone;

William Hartman; David Michael John Llster Arno, both of Toledo, all ofOhio [73] Assignee: Johns-Manville Corporation, ABSTRACT GreenwoodVillage Arapahoe An apparatus for winding continuous strands ofmatecounty Colo rial about rotating cores to form strand packages. is 22Filed; (y 29 973 provided with primary traversing mechanisms whichimpart a primary traversing motion to the strands as [21] Appl- (L679they are being wound on the packages whereby the strands progress andregress to define a series of [52 US. Cl. 242/43, 242/18 G g A secondarytraversing mechanism iS Provided 51 im. c1 36511 54/28 to impart aSecondary traversing motion of the strands 5 Field f Search 242/43 43213 G, 1 R relative to the packages to advance the series of bights backand forth across the peripheral face of the packages. The primarytraversing mechanisms each com- [56] References Cited firise a firstserjjefs a second serie; of ezfim members avmg outwar y acmg convex suraces or engaging UNITED STATES PATENTS the strands. The convex surfacesof the cam members 2,391,870 1/1946 Beach 242/43 of the first and SecondSeries face in Opposing (limo a g tions with the convex surfaces forsuccessive cam 3 056 711 lO/1962 III 242/1B G mfinlbers of each.seriesbeing Progressive/Y displaced 3:292:872 12/l966 Haydenw H 242/43relatlve to precedmg cam members in a d1r ect1on par- 3356304 12,1967GenSonW 242/43 X allel to the ax1s of rotat1on of the traversing mecha-3,399,841 9/1968 Genson.... 242/43 nism- With this Construction thefirst Series of Cum 3,414,956 12/1968 Genson 242/18 G X members move thestrands in one direction and the 3,695,523 10/1972 Genson et a1...242/43 X second series of cam members move the strands in an 3,784,121l/l974 Arno Ct al 242/43 pposite direction I 11 Claims, 8 DrawingFigures TRAVERSING MECHANISM BACKGROUND OF THE INVENTION The presentinvention is related to traversing mechanisms and particularly toimproved traversing mechanisms which effect a primary traversingmovement of a plurality of strands while maintaining the strandsseparated for the major part of the traversing movement withoutdestroying the integrity of the strands.

While other applications for the traversing mechanisms of the presentinvention may be found, the traversing mechanisms of the presentinvention are primarily intended for use in the manufacture ofcontinuous glass strands. In this instance, a plurality of continuousglass strands are drawn from a bushing and are wound onto packages. Thepackages produced in this operation are intended for use as sprayup gunrovings.

Thus, these packages must be void of loops, gobs and snarls so that theroving will readily unwind from a package and pass through the choppingoperations required in a sprayup gun roving operation.

Attempts to use a primary traversing mechanism comprising a plurality ofelongate straight elements which are supported in spaced-apart parallelrelationship to define a cylindrical pattern with the elements extendingat an oblique angle relative to the axis of rotation of the traversingmechanism (e.g. a birdcage traverse) for producing packages suitable forsprayup gun roving operations have been unsuccessful. Such traversingmechanisms are suitable for forming packages used for other purposes butfor sprayup gun roving operations they cause too wide a splitting of thestrands at their point of entry into the package, e.g. about a halfinch. Even though the birdcage type of traverse produces a packagesuitable for some chopping operations and maintains the integrity of thestrands wound onto the package, the wide splitting caused by this typeof traverse causes loops, gobs and snarls which are evident in the endsof the roving packages. These loops, gobs and snarls interfere withproper passage of the roving through guide eyes of a sprayup gun andcause breakouts and clogging when the roving passes through motor drivenchopper portions of such guns. Thus the package formed is unacceptablefor use in sprayup gun roving applications.

Prior art traverses include traverses illustrated in US. Pat. Nos. toHayden et al., No. 3,040,999 issued June 26, 1962; Hayden No. 3,292,872issued Dec. 20, 1966; Frickert No. 3,056,771 issued Oct. 2, 1962; GensonNo. 3,399,841 issued Sept. 3, 1968, and Genson No. 3,414,956 issued Dec.10, 1968. The Hayden patents work well with a single strand but causetoo great a split when used on a plurality of strands, thereby causingproblems similar to those experienced with the birdcage traverse. TheFrickert patent illustrates a traverse with a pair of spirally shapedcomplementary cam members for forming split strands which are broughttogether at spaced intervals. The first Genson patent relates to abarrel type traverse which is somewhat similar to the birdcage traversementioned above. The second Genson patent relates to a traverse with apair of straight cam members for traversing split strands with a combbeing used to help maintain the strands in a split relationship.

It is an object of the present invention to provide a traverse which,for the most part, maintains the strands in a split relationship butwhich brings the strands together at spaced intervals to form a packagesuitable for sprayup gun roving operations. The spread preferably doesnot exceed about a quarter inch at the point of entry of the strands tothe forming package. It is a further object to provide a traversingmechanism which does not destroy the integrity of the strands so thatthe strands do not break up during the sprayup gun roving operation intothe individual filaments making up the strands.

Accordingly, the present invention comprises a traversing mechanismhaving a first series of cam members and a second series of cam memberswhich are mounted for rotation about the axis of rotation of thetraversing mechanism. Each of the cam members has an outwardly facingconvex surface for engaging the strands and for maintaining the strandsin a split relationship except at spaced intervals when the strands aremomentarily brought together. The convex surfaces for the first'seriesof cams face in a direction opposing the convex surfaces of the secondseries of cams. The convex surfaces for the successive cam members ofeach of said series are progressively displaced relative to precedingcam members in a direction parallel to the axis of rotation of thetraversing mechanism whereby the first series of cam members move thestrands in one direction and the second series of cams move the strandsin the opposite direction. Preferably all of the convex surfaces havethe same radius of curvature and the convex surfaces are spaced radiallyoutward from the axis of rotation of the traversing mechanism.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevation of anapparatus for forming a plurality of multi-filament glass strands andfor winding the plurality of strands into packages;

FIG. 2 is an end elevation of the apparatus of FIG. 1 as viewed from theright of FIG. 1;

FIG. 3 is a perspective view of a first traversing mechanism of thepresent invention;

FIG. 4 illustrates one of the two sets of cam members of the traversingmechanism of FIG. 3;

FIG. 5 is a perspective view of a second traversing mechanism of thepresent invention;

FIG. 6 illustrates one of the two sets of cam members of the traversingmechanism of FIG. 5.

FIg. 7 is a perspective view of a third traversing mechanism of thepresent invention; and

FIG. 8 illustrates one of the two sets of cam members for the traversingmechanism of FIg. 7.

DETAILED DESCRIPTION AND PREFERRED EMBODIMENTS FIGS. 1 and 2 illustratea pair of traversing mechanisms 20 of the present invention which areutilized in an apparatus 22 for forming a plurality of multifilamentcontinuous glass strands. The apparatus 22 includes a glass-meltingreceptacle or bushing 24 from which a plurality of filaments 26, e.g.1,600 filaments, are drawn by rotating cores 28 that are mounted on arotating mandrel 30 which is driven by a motor 32. The filaments 26 aregathered into a plurality of strands 34, e.g. eight ZOO-filamentstrands, by converging rollers 36. The strands are then wound onto therotating cores 28 to form packages 38. Binders and the like are appliedto the filaments 26 as they are being drawn together to form the strands34 by a conventional binder applicator 40.

There are two traversing assemblies. The traversing mechanisms are theprimary traversing assembly and the traversing assembly 42 is thesecondary traversing assembly. The secondary traversing assembly 42includes a double-acting hydraulic piston and cylinder assembly 44 whichreciprocates the packages 38 back and forth relative to the traversingmechanisms 20 by moving the mandrel support 46. The packages 38 are eachcarried on the mandrel so that the centers of the packages 38 lie invertical planes which are centered relative to the series of strands 34being wound onto the particular package when the package is midway alongits traversing path. The length of the reciproeating movement of thesecondary traverse is regulated to form the packages 38 to the desiredwidth.

The traversing mechanisms 20 of the primary traversing assembly effect aseries of progressive and regressive bights of the strands. The seriesof bights is effected to deter the formation of a parallel lay ofadjacent windings. Thus, the primary traverse effects a series ofrapidly formed progressive and regressive bights of small amplitudewhile the secondary traverse effects a relatively slow progression ofthese bights across the package being formed to helically wrap theseries of bights back and forth across the entire width of the package.While the secondary traversing motion is generally effected by movingthe mandrel 30 relative to the traversing mechanisms 20 which are heldstationary, it will be understood that the secondary traversing actioncan be effected by holding the mandrel 30 stationary and moving theprimary traverses 20 in an axial direction relative to the mandrel 30.

As best shown in FIG. I and 2, the traversing mechanisms 20 are rotatedby a motor 48 and are rotatably mounted on pivotal mounting brackets 50.The brackets 50 are pivoted about an axis 52 by a mechanism 54 such asthat illustrated in U.S. Pat. No. 3,695,523 issued oct. 3, 1972, toSamual R. Genson et al. The primary traversing mechanisms 20 are movedaway from the winding axis of the packages 38 as the packages build upin diameter to maintain the traversing mechanism a desired distance awayfrom the peripheral surfaces of the packages being formed. While FIGS. 1and 2 illustrate an assembly wherein the primary traversing mechanisms20 are moved away from the packages 38, means can also be provided tomove the packages 38 away from the traversing mechanisms.

FIGS. 3 and 4 illustrate the first traversing mechanism 20 of thepresent invention which includes a plurality of elongated cylindricalrods or wires forming cam members which are mounted at each end incollars 62. The rods 60 extend parallel with respect to each other andlie in planes which contain the axis of rotation 64 of the traversemechanism. The rods 60 are spaced 45 from adjacent rods with the ends ofthe rods 60 being received within apertures of the collars 62. The rodsare secured to the collars by set screw 66, similar fastening devices,or by brazing.

There are two sets 68 and 70 of four cam members making up eachtraversing mechanism. FIG. 4 illustrates one of the sets 68. The otherset 70 of cam members comprises four complementary cam members which arethe mirror image of the cam members illustrated in FIG. 4. Complementarycam members of the two sets are located 180 apart and lie in the sameplane which also includes the axis of rotation 64 of the traversingmechanism.

Since the two sets of cam members are mirror images of each other, onlyone set of the cam members. set 68, will be discussed in detail to avoidunnecessary repetition. Each cam member 60 includes end portions 72 and74 which are mounted in the collars 62. The end portions 72 and 74 eachhave sections 76 and 78 which extend in a radial direction relative tothe axis of rotation of the traversing mechanism. In addition to the endportions, each cam member is provided with at least a first intermediateportion 80 which extends generally parallel to the axis of rotation 64of the traversing mechanism from the generally perpendicular section 76of end portion 72. Each of the cam members is provided with a convexportion 82 which has an outwardly facing convex surface. With the firstcam member of the set, the convex portion 82 extends between and mergeswith the intermediate section 80 and the perpendicular section 78. Atthe point where the intermediate portion 80 and the convex portion 82merge. there is an outwardly facing concave portion (e.g. with a radiusof curvature of about an inch) to assure a smooth transition betweenthese portions. For the second, third and fourth cam members of the set,the convex portion 82 merges with a second intermediate portion 84located intermediate the convex portion 82 and the perpendicular portion78. Intermediate portion 84 also extends in a generally paralleldirection relative to the axis of rotation of the traversing mechanism.

In the preferred embodiment of the traversing mechanism of FIGS. 3 and 4the radius of curvature of the convex portion 82 of each cam member isapproximately 5 inches with the traverse mechanism having a maximumdiameter of about 4% t 1 inches (4-96 inches is preferred) where theconvex portion 84 merges with the section 78 or the intermediate portion84 and a minimum diameter of about 3 i 1 inches (3 inches preferred) forportions 80 which hold the strands out from the axis of rotation of thetraverse to prevent the split between the strands from becoming toogreat. The entire cam member is about 6 inches long with the convexportion 82 for each successive cam member of a set being offset in adirection parallel to the axis of rotation of the traversing mechanismabout an inch relative to the convex portion of the preceding cammember.

With this traversing mechanism a contact between the strands and theconvex surfaces of the cam members maintains the strands in their splitor open relative positions while the strands are being moved side-waysby the action of the second. third and fourth cam members of each set.When the strands come into contact with the first cam member of one ofthe sets, the strands are momentarily pressed together as the cam memberchanges or reverses the direction of travel of the strands. The strandsthen split or open up again and remain split as they pass over theconvex surfaces of the second, third and fourth cam members of theparticular set. This cycle continues and the mechanism produces a splitstrand that is rovable and suitable for use in sprayup gun rovingoperations. The mechanism repetitively forces the four strands togetherfor an actual distance along the strands of 6 to 12 inches andsuccessively permits them to be apart for a distance of 4 to 8 feet withthe split for four strands being less than a quarter inch between theoutermost strands at the point of entry into the forming package. Withthis degree of split, loops, gobs and snarls are eliminated and theroving is easily unwound from the package thus formed and passed througha sprayup gun. 7

FIGS. 5 and 6 illustrate a second traversing mechanism 90 of the presentinvention. Like the first traverse mechanism 20, this traverse mechanismis mounted as shown in FIG. 1 and 2 and is made up of two sets 92 and 94of cam members 96 with one set of cam members being a mirror image ofthe other set of cam members. Complementary cam members of the two setsare located 180 apart and lie in the same plane which includes the axisof rotation of the traverse mechanism. Adjacent cam members are spacedrelative to each other a distance of 45. The cylindrical rods or wireswhich form the cam members 96 are mounted at each end in collars 98. Thecam members 96 extend parallel with respect to each other with the endsof the rods being received within apertures of the collars 98. The cammembers are secured to the collars by set screws 100, similar fasteningdevices or by brazing. Since one set of cam members is a mirror image ofthe other set of cam members, only set 92 will be described in detail toavoid unnecessary repetition.

Each cam member 96 includes end portions 102 and 104. The end portions102 of the cam members extend generally parallel to the axis of rotationof the traversing mechanism 90 and merge with outwardly facing convexportions 106 of the cam members. The end portions 104 extend generallyperpendicular to the axis of rotation of the traversing mechanism. Inthe first cam member of the set the end portion 104 merges with theconvex portion 106. However, for the second, third and fourth cammembers of the set the end portions 104 merge with an intermediateportion 108 which extends generally parallel to the axis of rotation ofthe traversing mechanism between the convex portion 106 and the endportion 104.

Preferably, the cam members 90 are about 4- /2 inches long with theradius of curvature of the convex portion 106 of each member being about2-5; inches. The maximum diameter of the traverse is about 5 inches andthe minimum diameter which corresponds with the diameter of end portions102 is about l- /z inches. The convex portions of the second, third andfourth cam members are displaced in a direction parallel to the axis ofrotation of the traversing mechanism about 96 inch relative to theconvex portions of preceding cam members.

With this traversing mechanism, the contact between the strands and theconvex surfaces of the cam members maintains the strands in their splitor open relative positions while the strands are being moved. sidewaysby the action of the second, third and fourth cam members of each set.When the strands come into contact with the first cam member of one ofthe sets, the strands are momentarily pressed together as the cam memberchanges or reverses the direction of travel of the strands. The strandsthen split or open up again and remain split as they pass over theconvex surfaces of the second, third and fourth cam members of theparticular set. While this traverse mechanism functions in a mannerquite similar to the first, there are no intermediate portionscorresponding to portions 80 of the first traversing mechanism to reducethe difference between the maximum and minimum effective diameters ofthe strand engaging portions of the traversing mechanism and to hold thestrands out from the axis of rotation of the traversing mechanism.Consequently, with this traverse mechanism, some of thevsplit strandsride down the convex surfaces and come too close to the axis of rotationof the traverse mechanism while other strands remain farther out on theconvex surfaces causing too great a split. The contact between thestrands and the cam members at radial distances from the axis ofrotation of the traverse which vary too much cause too great adifference in the length of the strands produced. This results in whatis termed a catenary wherein the variation in length between the strandsis such that some of the strands tend to form loops in the package.

FIGS. 7 and 8 illustrate the third traversing mechanism 110 of thepresent invention. Again, the traversing mechanism is made up of twosets, 112 and 114, of four cam members 116 each with one set of cammembers being the mirror image of the other set of cam members.Complementary cam members of the two sets are mounted on the traversingmechanism l apart with the cam members lying in a plane which alsocontains the axis of rotation of the traversing mechanism. Adjacent cammembers are spaced 45 apart and extend parallel with respect to eachother. The ends of the rods which form the cam members 116 are receivedwithin apertures of collars 118. The rods are secured to the collars byset screws 120, similar fastening devices or by brazing.

While the dimensions can vary, typically the cam members are about 6inches long. Each cam member has a first end portion 122 which extendsgenerally parallel to the axis of rotation of the traversing mechanismand a second end portion 124 which extends generally perpendicular tothe axis of rotation of the traversing mechanism. An outwardly facingconvex portion 126 of each of the cam elements merges with the endportion 122 and with an intermediate portion 128 which extends generallyparallel to the axis of rotation of the traversing mechanism. Theintermediate portion 128 extends between and merges with both the convexportion 126 and end portion 124. The convex portion 126 has a radius ofcurvature of about 5 inches. The maximum diameter of the traversingmechanism is about 2- inches and the minimum diameter of the traversingmechanism is about l- /fi inches. The convex portions are progressivelyspaced relative to preceding cam members of a set about 13/ 16 of aninch in a direction parallel to the axis of rotation of the traversemechanism.

With this traverse mechanism the contact between the strands and theconvex surfaces of the cam members maintains the strands in their splitor open relative positions while the strands are being moved side-waysby the action of the second, third and fourth cam members of each set.When the strands come into contact with the first cam member of one ofthe sets, the strands are momentarily pressed together as the cam memberchanges or reverses the direction of travel of the strands. The strandsthen split or open up again and remain split as they pass over theconvex surfaces of the second, third and fourth cam members of theparticular set. With this traverse mechanism the strands are split aboutthe same distance as with the first traverse mechanism. However, due tothe small diameter of the traverse mechanism, it has tended to give anonuniform split and a looping problem similar to that associated withthe second traverse mechanism is present.

While all of the cam members of the traverse mechanism shown are madewith bent wire, the cam members can be made with other equivalentmembers which would give the same type of point contact between thestrands and cam members that the wires provide.

What is claimed is:

1. An apparatus for winding a plurality of continuous strands offlexible material about a core to form a package which apparatusincludes a source of said strands, means for rotating said core about afirst axis, a traversing mechanism rotatable about a second axisparallel to said first axis and adjacent to a peripheral surface of saidpackage for imparting primary traversing motions to said strands as theyare being wound on said package whereby said strands progress andregress to define a series of bights, and means for imparting asecondary traversing motion to the strands relative to the package toadvance the series of bights across the peripheral surface of thepackage, the improvement comprising: said traversing mechanismcomprising a first series of cam members and a second series of cammembers, mounting means for supporting said cam members in fixedrelative positions for rotation about the axis of rotation of saidtraversing mechanism, each of said cam member lying in a planecontaining the axis of rotatioh of rotation of said traversingmechanism, each of said cam members having an outwardly facing convexsurface extending in a direction parallel to the axis of rotation ofsaid traversing mechanism for engaging the strands, said convex surfacesof said first series facing in a first direction and said convexsurfaces of said second series facing in a second direction opposingsaid first direction with said convex surfaces for succesisve cammembers of said cam members of both of said series being progressivelydisplaced relative to said convex surfaces of preceding cam members ofsaid cam members in a direction parallel to the axis of rotation of saidtraversing mechanism whereby the first series of cam members move thestrands in said first direction and the second series of cam membersmove said strands in said second direction while maintaining the strandsin a split relationship for the major portion of their movement andbringing said strands together at spaced intervals.

2. The improvement as defined in claim 1 wherein: there are four of saidcam members in each series with each of said cam membersbeing spaced 45from adjacent cam members and with said cam members of said first andsecond series being spaced from said cam members of the other serieswhich are complementary.

3. The improvement as defined in claim 1 wherein each of said convexsurfaces of said cam members has substantially the same radius ofcurvature with said cam members of said first and said second serieswhich are spaced apart 180 being mirror images of each other.

4. The improvement as defined in claim 1 wherein each of said cammembers has limiting means adjacent an inner end of said convex surfacesof said cam member for limiting the spacing between said split strands.

5. The improvement as defined in claim 4 wherein said limiting meanscomprises a second surface of said cam member merging with said convexsurface end extending generally parallel with respect to said axis ofrotation of said traversing mechanism.

6. The improvement as defined in claim 5 wherein the radius of curvatureof said convex surface of each of said cam members is about five inches.

7. The improvement as defined in claim 6 wherein said second surface isspaced radially outward from said axis of rotation of said traversingmechanism with minimum and maximum effective diameters of strand contactsurfaces defined by said second surface and said convex surface of saidtraverse mechanism being about 3 i 1 inches and about 4-% i- 1 inchesrespectively.

8. The improvement as defined in claim 6 wherein minimum and maximumeffective diameters of strand contacting surfaces of second surface andsaid convex surface are about 2- /2 inches and about l- /fi inchesrespectively.

9. The improvement as defined in claim 6 wherein maximum and minimumeffective diameters of strand contacting surfaces of said second surfaceand said convex surface differ by about 1 inch to about l-Vz inches.

10. The improvement as defined in claim 1 wherein the radius ofcurvature for the convex surface of each of said cam members is about2-% inches.

11. The improvement as defined in claim 1 wherein: said cam members arerods having rounded surfaces for contacting said strands with said cammembers contacting said strands at spaced points along said strands. a:

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTIONPATENT NO. 3, 861, 608

DATED January 21, 1975 INV ENTOR(S) J. G. Mohr, et a1 It is certifiedthat error appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Column 3, line 38 "October" is not capitolized Column 5, line 42 "1-1/2"should read "1-1/4" Column 8, line 15 "end" should read "and" Signed andSealed this twent zrst a 0 [SEAL] yf D y f 0Cl0b6f1975 A ttes t:

RUTH C. MASON Commissioner oj'Parents and Trademarks

1. An apparatus for winding a plurality of continuous strands offlexible material about a core to form a package which apparatusincludes a source of said strands, means for rotating said core about afirst axis, a traversing mechanism rotatable about a second axisparallel to said first axis and adjacent to a peripheral surface of saidpackage for imparting primary traversing motions to said strands as theyare being wound on said package whereby said strands progress andregress to define a series of bights, and means for imparting asecondary traversing motion to the strands relative to the package toadvance the series of bights across the peripheral surface of thepackage, the improvement comprising: said traversing mechanismcomprising a first series of cam members and a second series of cammembers, mounting means for suPporting said cam members in fixedrelative positions for rotation about the axis of rotation of saidtraversing mechanism, each of said cam member lying in a planecontaining the axis of rotation of rotation of said traversingmechanism, each of said cam members having an outwardly facing convexsurface extending in a direction parallel to the axis of rotation ofsaid traversing mechanism for engaging the strands, said convex surfacesof said first series facing in a first direction and said convexsurfaces of said second series facing in a second direction opposingsaid first direction with said convex surfaces for succesisve cammembers of said cam members of both of said series being progressivelydisplaced relative to said convex surfaces of preceding cam members ofsaid cam members in a direction parallel to the axis of rotation of saidtraversing mechanism whereby the first series of cam members move thestrands in said first direction and the second series of cam membersmove said strands in said second direction while maintaining the strandsin a split relationship for the major portion of their movement andbringing said strands together at spaced intervals.
 2. The improvementas defined in claim 1 wherein: there are four of said cam members ineach series with each of said cam members being spaced 45* from adjacentcam members and with said cam members of said first and second seriesbeing spaced 180* from said cam members of the other series which arecomplementary.
 3. The improvement as defined in claim 1 wherein each ofsaid convex surfaces of said cam members has substantially the sameradius of curvature with said cam members of said first and said secondseries which are spaced apart 180* being mirror images of each other. 4.The improvement as defined in claim 1 wherein each of said cam membershas limiting means adjacent an inner end of said convex surfaces of saidcam member for limiting the spacing between said split strands.
 5. Theimprovement as defined in claim 4 wherein said limiting means comprisesa second surface of said cam member merging with said convex surface endextending generally parallel with respect to said axis of rotation ofsaid traversing mechanism.
 6. The improvement as defined in claim 5wherein the radius of curvature of said convex surface of each of saidcam members is about five inches.
 7. The improvement as defined in claim6 wherein said second surface is spaced radially outward from said axisof rotation of said traversing mechanism with minimum and maximumeffective diameters of strand contact surfaces defined by said secondsurface and said convex surface of said traverse mechanism being about3 + or - 1 inches and about 4- 1/2 + or - 1 inches respectively.
 8. Theimprovement as defined in claim 6 wherein minimum and maximum effectivediameters of strand contacting surfaces of second surface and saidconvex surface are about 2- 1/2 inches and about 1- 1/2 inchesrespectively.
 9. The improvement as defined in claim 6 wherein maximumand minimum effective diameters of strand contacting surfaces of saidsecond surface and said convex surface differ by about 1 inch to about1- 1/2 inches.
 10. The improvement as defined in claim 1 wherein theradius of curvature for the convex surface of each of said cam membersis about 2- 1/2 inches.
 11. The improvement as defined in claim 1wherein: said cam members are rods having rounded surfaces forcontacting said strands with said cam members contacting said strands atspaced points along said strands.